DESCRIPTION (provided by applicant Participants of syringe exchange programs (SEPs) routinely suffer from untreated or under-treated substance use disorder, a situation that is associated with significant individual and public health costs (Degenjardt et al., 2010). These individuals are also routinely embedded within social networks that reinforce continued drug use and risk behaviors (Latkin et al., 2013a). The welfare of these individuals and the public's health can be improved by interventions directed toward reducing drug use risks and expanding drug-free support (Kidorf & King, 2008). Previous work by our research group has demonstrated that an intervention combining a risk reduction/treatment readiness group with behavioral contingencies is highly associated with increased rates of treatment enrollment and re-engagement, and reduced rates of drug use and injection behaviors, for up to one year (e.g., Kidorf et al., 2009). The present R34 application extends this work by adding a new component to the risk reduction/treatment readiness group designed to expand social support and facilitate social network change. This intervention requires SEP registrants to attend the group with a drug-free family or friend from their personal network that can provide stable support and encourage harm reduction and treatment seeking. This intervention uses an alteration network change model (Valente, 2012) and posits that repeated exposure to drug-free community support collaterally reduces exposure to network members that support risk behaviors. This model also provides a pathway to modifying existing social networks by facilitating interaction with the personal social networks of drug-free family and friends. The intervention is supported by research showing that substance users report substantial pockets of drug-free family or friends in their social networks (Bohnert et al., 2010; Kidorf et al., 2005b). It is also supportedby community reinforcement principles that have shown efficacy in treatment samples (Roozen et al., 2004), but have not been applied to out-of-treatment drug users. The study will activate and characterize drug-free support in the personal social networks of SEP participants, evaluate the feasibility of a 6-week Community Supported Risk Reduction intervention that partners with drug- free family and friends, and evaluate the efficacy of this intervention over 6-months. Primary outcomes include changes in 1) network support for reducing drug use, and 2) injection risk behaviors (sharing equipment, rates of use), while secondary analyses will evaluate changes in time spent with drug using and non-using individuals. Data will be used to support an RCT isolating the benefits of community involvement for reducing risks, expanding drug-free support, and facilitating social network change.